The comments were made following reports on Tuesday afternoon of a breakthrough in the talks between EU and UK negotiators.

The deal will be the focus of a crunch Cabinet meeting at Downing Street on Wednesday afternoon.

British Cabinet ministers were invited to read the papers relating to the draft deal on Tuesday night ahead of the special meeting of Theresa May’s senior team “to decide on next steps”.

The Irish Government spokesman described the situation as “fast-moving”.

He confirmed the Irish position on the backstop had not changed, adding that “a number of issues were outstanding”.

In another sign that Dublin may not be happy, a spokesman for Ireland’s deputy premier Simon Coveney said: “Negotiations between the EU and UK on a withdrawal agreement are ongoing and have not concluded.”

He also said a “number of issues are outstanding”, adding that negotiations were at an “extremely sensitive” juncture.

Members of Ireland’s opposition gave a cautious welcome to the reported deal.

Labour Party leader Brendan Howlin said any agreement needed to ensure there was “a permanent backstop to protect a borderless Ireland”.

“We need to see the text, we need to see exactly what has been agreed, what are the implications for the border issue, for trade,” she said.

Ms Chambers added that a deal that included the UK staying within the customs union would be the best outcome for Ireland because east-west trade was “so important”.

Independent TD Thomas Pringle said he needed to see the details before commenting because it could have “potentially very negative effects for the border if it’s wrong”.

Sinn Fein’s David Cullinane said: “We’ve always said that the backstop and the insurance policy which has to be put in place for Ireland has to be long term, has to be durable, has to be permanent.

“It has to give protection to the people of Ireland that we need, which is to avoid a hardening of the border to protect the Good Friday Agreement in all its parts and to protect the rights of citizens.”

Earlier in the Dail, Taoiseach Leo Varadkar would not comment on reports that a text had been agreed taking into account the Irish border question.

Minutes after reports of a deal emerged, Mr Varadkar would not answer questions from Fianna Fail, Sinn Fein or the Labour Party on the matter.